This invention relates to apparatus for the sharpening and/or bevelling of a ski or snowboard edges.
Until recently, ski designs have had a conventional side-cut (a turning radius of between 30 and 40 meters). With the recent increase in popularity of xe2x80x9cshapedxe2x80x9d or xe2x80x9csuper side-cutxe2x80x9d skis, side cut has become more pronounced whereby a ski is more narrow in the waist than it is in the shovel and the tail, making it easier to carve a turn (a turning radius of between 10.5 and 30 meters). This is relevant as up until recently it has been possible to sharpen and bevel the side edge of a ski with conventional side-cut by positioning a file lengthwise on a guide to sharpen and bevel the side edge. This is not the best position to place the file however, as with even a small amount of side-cut, the teeth of the file only contact the edge at two places along the length of the file (front and back). This is even more pronounced with shaped skis, making the sharpening/bevelling job difficult and inefficient at best. Ski and snowboard camber is also a factor. U.S. Pat. 4,030,382 to Nilsson et al shows an attempt to compensate for this by using a clamping screw to bend a file blade between two support ribs.
A further factor is that the inherent angle of the teeth on commercially available files when positioned lengthwise on the metal edge does not produce the best cut when the file is pulled along the length of the edge. For example, the standard angle of teeth for a lathe cut file is 48 degrees. It is when the file is rotated somewhat so that the angle of the teeth is effectively 60 degrees or more that a better and more efficient cut is achieved (the file teeth are better oriented in relation to the direction of the cut along the edge).
Another consideration is that of providing the required bevel angle on the side edge or base edge. Leitinger (DE 3233682 A1) employs an eccentric disc system to achieve a selected edge bevel angle, which prior art system includes moving parts and general wear and tear can cause the angle to vary in an undesirable manner.
It is the main object of this invention to provide a ski/snowboard edge dressing system that alleviates problems inherent in prior art systems and that is simple, inexpensive, portable and easy to use while minimizing the fatigue and effort required to perform accurate and consistent edge sharpening/bevelling especially on xe2x80x9cshapedxe2x80x9d or xe2x80x9csuper side-cutxe2x80x9d equipment as described above.
Accordingly the invention in one aspect provides: apparatus for the sharpening and/or bevelling of either a ski or a snowboard side edge or base edge, said apparatus comprising a guide adapted to be held by the hand and moved lengthwise along an edge portion of a ski or snowboard while in contact with a surface thereof, said guide including means for securing a file or the like thereto at any one of a plurality of desired angular positions relative to the lengthwise direction of movement of the guide during use such that a desired portion of the file length may make contact with the edge portion of the ski or snowboard and/or the teeth on the file may be oriented at a desired angle to the lengthwise direction of movement thus assisting in producing a consistent file cut and efficient edge sharpening or bevelling edges of the ski or snowboard.
In accordance with a preferred feature of the invention said means for securing comprises means for clamping said file or the like in said guide in any one of the desired angular positions.
As a further preferred feature of the invention said guide includes means to angularly orient the file or the like in a plane transverse to said lengthwise direction when positioned at a side edge portion of a ski or snowboard to establish a desired side edge geometry or bevel angle.
Preferably said means to angularly orient said file or the like includes plural elements of selected dimensions positionable in a selected manner in said guide to engage a surface of the ski or snowboard and to establish a selected angular orientation of said guide and the file or the like secured therein in said transverse plane relative to the ski or snowboard.
In accordance with a still further preferred feature of the invention said guide includes a slot-like passage therethrough for receiving said file or the like and said means for clamping comprising a clamp plate adapted to cooperate with a wall of said passage to secure the file or the like therein.
In a preferred embodiment of the invention said guide defines a pair of said passages generally at right angles to one another, each said passage having one said clamp plate respectively associated therewith.
In accordance with a further aspect of the invention there is provided: apparatus for the sharpening and/or bevelling of either a ski or a snowboard side edge or base edge, said apparatus comprising a guide adapted to be held by the hand and moved lengthwise along an edge portion of a ski or snowboard while in contact with a surface thereof, said guide including means for securing a file or the like thereto such that in use a desired portion of the file may make contact with the edge portion of the ski or snowboard thus effecting edge sharpening or bevelling, said guide including means to angularly orient the file or the like in a plane transverse to said lengthwise direction when positioned at the side or base edge portion of the ski or snowboard to establish a desired edge geometry or bevel angle.
In a preferred form of the further aspect of the invention said means to angularly orient said file or the like includes plural elements of selected dimensions (e.g. pegs) positionable in a selected manner in said guide to engage a surface of the ski or snowboard and to establish a selected angular orientation of said guide and the file or the like secured therein in said transverse plane relative to the ski or snowboard.
In a preferred embodiment of the further aspect of the invention said guide includes means for clamping said file or the like in said guide in any one of a plurality of desired angular positions relative to the lengthwise direction of movement of the guide during use so that a desired portion of the file length may make contact with the edge to promote efficient edge sharpening and bevelling. In this further aspect said guide preferably includes a slot-like passage therethrough for receiving said file or the like and said means for clamping comprising a clamp plate adapted to cooperate with a wall of said passage to secure the file or the like therein.
Further features and advantages of the invention will become more readily apparent from the following description of a preferred embodiment of same: